Summary auto-generated
This study used PCR methodology to detect Streptococcus mutans and S. sobrinus in dental plaque samples from 77 Japanese pre-school children aged 3-5 years and correlated their presence with dental caries incidence. Plaque samples were collected by brushing all erupted teeth with a sterile toothbrush, and dental caries were assessed using WHO diagnostic criteria. PCR detection proved more sensitive than conventional culture methods. Overall, S. mutans was found in 72.8% of children and S. sobrinus in 61.1%. Children harboring both species (48.1%) had significantly higher caries scores (dmft) compared to those with S. mutans alone (24.7%). Additionally, 13.0% had only S. sobrinus, and 14.3% were negative for both bacteria. Among caries-free children, over half still carried at least one mutans streptococcal species, suggesting other virulence factors influence caries development. The findings demonstrate that co-colonization with both S. mutans and S. sobrinus is associated with substantially higher caries prevalence in pre-school children.
Key findings
- Children carrying both S. mutans and S. sobrinus had significantly higher dental caries prevalence (dmft scores) than those with S. mutans alone
- PCR detection proved more sensitive than conventional culture methods for identifying mutans streptococci species
- Among 77 pre-school children, 72.8% were positive for S. mutans, 61.1% for S. sobrinus, with 48.1% harboring both species simultaneously
- Approximately 16.9% of children were caries-free despite carrying mutans streptococci, indicating that bacterial presence alone does not determine caries risk
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
Streptococcus mutans and S. sobrinus are associated with the development of dental caries. These bacteria were detected by PCR and then their presence was compared with the incidence of dental caries in 77 Japanese pre-school children. Plaque samples were collected from all erupted tooth sites in the subjects, aged 35 years old and each with primary dentition, with a sterile toothbrush. A dental examination was performed for dmft (decayed, missing, filled, total) with the WHO caries diagnostic criteria. In all subjects, the prevalence of S. mutans and S. sobrinus was 72.8% and 61.1%, respectively; 19 (24.7%) were positive for S. mutans alone, 10 (13.0%) were positive for S. sobrinus alone, 37 (48.1%) were positive for both S. mutans and S. sobrinus, and 11 (14.3%) were negative for both S. mutans and S. sobrinus. The dmft scores of children positive for both S. mutans and S. sobrinus were significantly higher than those positive for S. mutans alone. These results indicate that children harbouring both S. mutans and S. sobrinus have a significantly higher incidence of dental caries than those with S. mutans alone.